Charcoal retort



June 21, 1960 J. R. wlLKlNs 2,941,927

cHARcoALREToRT Filed Sept. 28, 1956 4 Sheets-Sheet 1 1.08 FIG. u lo) 2O28 CHARGING PRE-HEATING CARBONIZING PRECOOLING QDISCHARGE JOHN R.WILKINS ATTORNB June 2l, 1960 J. R. wlLKlNs 2,941,927

CHARCOAL RETORT Filed Sept. 28, 1956 4 Sheets-Sheet 2 INVENTOR JOHN R.WILKINS VA y J. R. WILKINS CHARCOAL RETORT June 21, 1960 Filed Sept. 28,1956 4 Sheets-Sheet 3 INVENTOR JO HN R. WILKINS i ATTORNEYS J. R.wlLKlNs cHARcoAL RETORT June 21, 1960 4 Sheets-Sheet 4 Filed Sept. 28,1956 INVENTOR JOHN R. WILKINS ATTORNEYS nite States Patentt O CHRCOAL-RETRT Y John Riley Wilkins,P.0. Box 307, Steelville, Mo. Filed Sept.28,'L 1956, Sel'. N0. 612,737A

2 Claims. (Cl. 20L-9.8)

This invention relates-toY lthe-carbonizati'on' of wood' and moreparticularly to improvedA apparatus and method of making charcoal. Oneof the problems heretofore presentin the carbonization of wood is thataconsiderable amount of the -heat requiredto carbonize'tlie-woo'd' islost or otherwise dissipated outside the retortlsothatl the' heat is loteciently utilize'd'todo 'the Work offmakingY charco Accordingly, it is`an object of the present invention to provide a charcoal retort havingimprovedY means for tiring the wood or other material which is `to b ecarbonized, which means is highly eicient and results in a minimum ofheat loss so that a maximum amount of the heat generated is utilized inthe carbonizing of the Wood.

Another problem in producing charcoal resides in the cooling of `thecarbonized wood after the samehas been heated suil'lciently to drive olithe distillation products. Unless the temperature of the charcoal isreduced below that capable of firing' the same upon contact with oxygen,ignition will occur and, consequently, reduction in the quality of thecharcoal results.

It is, therefore, another objectof the invention to provide a retort ofthe type described having improved means for cooling the carbonizedmaterial under accurately controlled conditions so as to eliminate thevpossibility of ignition by maintaining the carbonized material out of-contact wth oxygenaconta'ininggas until thecarbonized material has beencooled to alow enough tempera-ture to precludeignition katatmosphericcon'ditions.'

A still further object of the present-invention is the provision of acharcoal retort of the' type described which is substantially continuousin operation, which insures an .accurate temperature control of thecharcoal during carboniztion and which insures the coolingof the;charcoal with a minimum danger of ignition.

A still further object of the presentl invention is the provision of -acharcoal retort of the type described having improved means for handlingthe charges as they move through the retort chambers.

Still another object of the present invention is the` provision of anovel method of making charcoal which embodies the steps of continuouslyintroducing charges of.

-discharging the charges into a receiving chamber wherel they arefinally cooled while substantially preventing any contact therewith ofan oXygen-containing' gas.

A further object of the present invention is the provii Ptented June 21,1960 ice 2f Still? anothen object;v ofi the: invention.y is; theprovision of afzretortoftthetypezdescribed.A havingl improved-.meansfor'recoveringrthez combustible gases driven, oil iirornJ theWoodilorotherr material duringcarboni'zation, thereof; and utilizing thecombustible; gases to. provideheat .for further car-bonization.

Still anotheriobjectiofgthe inventionisthe provision-of az retort of:the. type .described having; improved means for dischargingYsuccessivexcharges from. the heating ,chamber lafter carbonization andsome cooling hasbeencompleted.

These-` and` other. objectsVA will become more. apparent during the;course of-ftheiollowing detailedV description and appendedfclaims.

The. invention may; bestbe understood. with:V reference to theYaccompanyingdrawings: wherein an` illustrative embodiment is shown.

Inthedravvings:l

Figurel isfa .somewhatschematic side. elevational View ofl a retortembodying theaprinciplesof .the present. invention;

Figure4 2 is, an, enlarged. end. view of` the; retort. with parts brokenaway lfor'thepurpose offclearer illustration;

Figure 3 is ar vertical sectional View of the entrance chamber-of theyretort: illustrating the, manner in lwhich successive -charges are',vmoved `from Y.the :entrance chamber into=theheatingchamber of theretort;l

Figure 4 isa side elevational view of the discharge tend of the.retortwith parts. broken away to;l illustrate the manner in whichsuccessive:chargesareVr removedfrom thefiringchamber and discharged,into the; cooling.4 chamber; and' Figure 5 is across-sectional ,viewtakenalong lineSg-S of Figure 4.

Referring now more-particularly to. the` dra-,vs fings, lthere is shownin Figure l4 -a schematic view of a retort, generally' indicated. at10,V embodying, the principles.- oithe present invention. The retort ispreferably oontinuous--v in nature and disposed in a straightlinesofthat.' Successive charges of-.wood or. othermaterialto-becarbonizedfmay be introduced into the ifront. end: and.vdischarged. after carbonization has been completed from the rearA endthereof. Of course, while itis preferred to construct the retort inastraight relationship it will be apparenti that acircuitous-path may beemployed, if desired. Ingeneral, the retort isv divided into fourseparatecompartments or chambers. Preferably, the rst. threecompartments areV in general longitudinal. alignment with each. otherwhile theflatter two. may bev vertically stacked, asv will hereinafterbe more.. fullyY described.

Theforwardend of the retort deiines anentnancecompartmentor chamber, 1-2which is arranged to receivesuccessive bins or` hampers 14 charged withsuitably formed wood or other. material to be: converted into charcoal.Figure 3 illustratesv generally. theconstruction ofr the bins or hamperswhich are preferably handled when outside the retort by wheeledcarts ordolliesY 16. Disposed wit-hin the entrance chamber` 12 is ameansgenerally indicated at 18, for receiving theV hampers and formoving the lsame into a central tiring or heatingcompartment or chamber20 of the retort. The. entrance chamber V12 is, closed. at its forwardend'v by doors` 22, and at vertically movable door 24 is disposed' at.its other endr between the., entrance chamber 12 land ringl chamber 20.The. means 18is arranged to move successive charged hampers. from theentrance chamber whereinthey are supported bythe dollies l1'6Y throughthe door. 24. land into thef heating or tiring chamber 20. Inside thefiring, chamber there. is. plolvi'ded suitable heating means, generallyindicated` at 2.6,fwliich is arranged so that successive charges duringtheir. travel through the firing` chamber are yfirst preheated, thencarbonized and iinally precooled to aY substantial extent. After theprecooling of'- successive charges has been faccomplished, the latterare moved out of the firing chamber and into a discharge compartment orchamber, generally indicated at 28. A means is provided within thedischarge chamber 28 for opening and closing off the iring chamber withrespect to the discharge chamber, for receiving the precooled carbonizedwood-containing hampers from the tiring chamber and moving the same intothe discharging chamber, and for discharging the contents of the hampersinto a receiving and cooling chamber or compartment, generally indicatedat 32. The opening and closing means is also operable to discharge theempty hampers from the discharge chamber at the rear end of the retort.

In general, the operation of the retort is carried on substantiallycontinuously so that when a charged hamper 14 is -moved from theentrance chamber 12 into the ring chamber 20 nby the operation of themeans 18, a

hamper containing carbonized and precooled material will besimultaneously moved out of the rear end of the tiring chamber 20 andinto the discharge chamber 28. The means 30 in the discharging chamberthen dumps the charge from the hamper and discharges the empty hamper atthe rear end of the retort.

The retort is preferably arranged so that the forward end is at anelevation slightly higher than the rearward end. That is, the retort isIprovided with a `gradual slope of the order of -one degree whichfacilitates the movement of the hampers therethrough. Of course, theoperation of the retort can be carried out on any time cycle,

but of primary significance is the fact that the entire operation isautomatic so as to reduce to a minimum the requirements for attendants.The hampers which have been passed through the firing chamber aresubsequently handled in a substantially oxygen-free chamber by meanscapable of dumping the carbonized and precooled contents thereof into acooling chamber which likewise is maintained substantially free ofoxygen. This discharging operation could not 'be accomplished manuallysince the temperatures present would prevent an attendant from gainingaccess thereto. Hence, the present arrangement insures that thecarbonized material will be cooled to a suiciently low temperature,without ignition, so that when the same is finally brought into contactwith oxygencontaining gas, ignition is no longer possible.

Referring now more particularly to Figure 3, vthe construction oftheentrance chamber 12 of the retort is shown in detail as includingvertical sidewalls 34 connected at their upper ends by an upper wall 36.The floor of theV chamber is preferably provided with tracks 38 forreceiving and guiding the dollies 16. The dollies 16 may be of anysuitable construction and, as shown in Figure 3, include a skeletonizedframe 40 mounted on wheels 42. Suitably mounted on the upper surface ofthe frame 40 is a plurality of longitudinally spaced rollers 44 havingouter anges 46 thereon disposed to receive and guide the lower surfaceof the hampers 14.

The hampers 14 may also be of any suitable construction and, as shown,include a skeletonized box-like frame 48 having upper transverse endmembers 59 extending across the forward and rearward extremitiesthereof.

Extending upwardly from the upper end of the skeletonized frame 48 at aposition spaced inwardly from each end thereof -is a pair of uprightrigid members 52'carrying rollers 54 on the upper ends thereof.

The means 18 comprises a huid pressure-operated ram unit 56 suitablymounted on the exterior of the chamber 12, as by bracket 57, in aposition above the forward door 22 thereof. The ram unit 56 includes aplunger 58 which extends through the forward wall of the chamber 12above the door 22 and into the chamber. Pivotally mounted on therearward end of the plunger 58 is a hamper-engaging arm or member `60. Aspring 62 is connected between the element 60 and the plunger so as toresiliently urge the latter against a stop element 64 rigidly secured tothe plunger S8. In this manner, a fully charged hamper moved into theentrance chamber 12 through the doors 22 will engage the element 60 andmove the same Irearwardly until the hamper reaches it fully extendedposition within the charging chamber. At this point, the trailing-transverse member S0 of the hamper will have passed beyond the element60 and the spring 62 will act to move the latter into a position 'behindthe transverse member 50. This position is illustrated in Figure 3 andit will be noted that upon actuation of the fluid pressure-operated ramunit 56, as by suitable controls, not shown, the hamper 14 may be movedfrom the entrance chamber 12 into the heating or firing chamber 20 whenthe door 24 is open.

The door 24 is mounted for vertical sliding movement in an aperturedpartition `66 separating the chambers 12 and 20. Mounted on each side ofthe door 24 is a vertically extending rack 63. Each rack is engaged by akpinion 70 mounted on a common shaft 72 rotatably supported by anysuitable means above the upper wall of the entrance chamber 12. Ihepinions 70 may be rotated by any suitable means, such as a reversiblemotor 74, connected to drive the shaft 72 as by a pair of sprockets 76and a cha-in 78 trained thereabout. It will be understood that 'byactuating the motor 74 selectively in either direction, the door 24 maybe selectively moved into an upper open position or a lower closedposition.

The heating or firing chamber 20 preferably comprises side wails 80,each of which includes an exterior plate 82 of metal or the like and aninterior wall 84 of brick or other refractory material and anintermediate layer 86 of a suitable insulating material. An upper Wall88 extends between the upper ends of the side walls 89 and includes anexterior plate 90 and interior transversely extending I-beams 92 or thelike mounted on the upper ends of the interior walls 84. A layer ofinsulation 94 is mounted between the beams 92 and the exterior plate 90.Extending downwardly from the I-beams 92 is a plurality of hangers 96which support a longitudinal housing 98 extending throughout the entirefiring compartment 20. The housing 98 is rectangular in cross sectionand has a pair of transversely spaced tracks 100 mounted on the interiorsurface of the upper wall thereof. The tracks 100 may be of any suitableconstruction and (as shown, are in the form of conventional i-beamswhich provide channels within which the rollers 54 of the hampers 14-may ride. The tracks lf3@ thus serve to support the hampers in thetiring chamber for movement through the housing 98 thereof.

As best shown in Figures l and 2, the heating means 26 preferablycomprises a plurality of gas burners 102. These burners are disposed inthe lower portion of the firing chamber below the housing 98 therein,which lower portion terminates intermediate the ends of the chamber 20,as shown in Figure 1. r[he terminal end of the lower portion of thechamber is open to the atmosphere, as at 104, for the introduction ofair sufficient to support combustion of the burners. The forward end ofthe retort adjacent the entrance door 22 includes a lateral passageway106 which leads to a stack 10S through which the com-bustion air in thetiring chamber may discharge.

Of course, the placement of the burners with respect to the firingcompartment will vary in accordance with the capacity of the retort. Asshown, the first burner is disposed approximately midway between theends of the chamber. There are two additional burners provided which arespaced toward the discharge end of the cham- *ber and disposed withinthe area defined by the irst burner and the opening |104 in the lowerportion of the compartment. Of course, the heat generated by the burnerswill be Imost intense in the area immediately above the burners andlSince the ow of heated air is toward the forward end of the ringchamber, the rear end of the chamber will have the lowest temperature,with the temperature of the forward end gradually diminishingtowardthefstaclc. In this mannen; the fresh charges. entering the tiringchamber through the door 24rwil1 be preheated during their movementthrough the housing 98'for approximately one-half of their travel. Thisrst areaconstitutes a-preheating area'where the sap. ormoisture in thewood or material being treated is driven off. Next, the charges enter acanbonizing. area which is: immediately abovethe burners whereY theproducts. of distillation are driven off. Sincefthe pressurecreated--bythe heat Within the housing- 98 is greater than atmospheric pressure,the products of distillation can. be conveniently directedto the burners102, as by pipes or. conduits 110. In this manner, the combustible gasesdrivenoff inthe carbonizing processare utilized to tire-the burners,thus greatly increasing the. eiciency ofthe retort.l After. thecanbonizing area immediately above the burners 102 has been passed,thecarbonized chargesmove toward .the rear endof the-.fringchamber whichconstitutesY aprecooling area thereof. During this portion of. travelthetemperature ofthe charges is substantially reduced..

The discharging cham-ber 28 comprises a substantially semi-cylindricalvertical wall 112 of any suitable construction extending from oppositesides ofthe. rear end ofthe tiring. chamber and having an upper. wall114 covering. the same. Extending along the portion ofthe cylindricalwall112 adjacent the end of lthe firing.V chamber 20 are upper and lowerclosure guide elements 116 within. which `an arcuate closure member l118is slidably mounted. The closure member 1:1Svincludes an opening 120.which isarranged'to 'be moved between a position adjacent the rear endofthe tiring compartment to permit discharge of the hampers therefromand' a position adjacent an. openingV 122 in the wall 112 which enablesthe empty hampers to be discharged from the chamber 28.

As best shown in -Figure 4, the closure member 118 includes rigid arms124 extending radially therefrom to a verticalY shaft. 126 pivotallysupported at itslow'er end on a Ibearing block 128 or the like suitablymounted on the iloor of the discharge chamber. At the upper end oftheshaftV 124, the upper walll1f12,A is provided` in a position Ito engagetheV inner periphery of" the ring` plate 132. In this manner, the upperend of -t-he shaft is mountedfor pivotal movement andasubstantiallyairtight seal impervious to heat is formed at' the pointwhere the shaft extends out of the discharger chamber.

The shaft 126 and hence the closuremember 118 is.

selectively moved in either direction =by' any suitable means, such as areversible electric motor'1'40 secured to the exterior of the upper wallas bybracket 142. The drive shaft of the motor 140 is provided withk apinion 144 arranged to -drive a large spur gear'146 or the like rigidlymounted on the upper extremity of the shaft 126.

The central portion of the shaft`126f is formed with a v horizontalaperture 148 and a horizontal sleeve 150 is rigidly'secured, asbybracing 152, to the shaft 12'6'in Yalignment with the aperture 148 andextends'towardithe closure member 118. A screw conveyor 154'hasvitsrearward. endA portion journaled within the sleeve 150` and shaftaperture 148 and its forward end extendingY to a point adjacent theclosure member opening120.V The screw conveyor 154 is thus mounted'forpivotal movementwiththe shaft 126 and is rotated about its own axis:by, anyv suitable means, rsuch as a reversi-ble electric motor.156-fixedly mounted. on the gear 146. I'he drive shaft of the motor156is. provided with a pinion 158 V.Which meshes with `a cooperatinggear160-xed to the upper end of. a verticalr conveyor drive shaft 162. Theshaft! 162 extends. downwardly through suitablegasketed aperturesformed-inthe gear 146 and plates 136 to a point adjacent therear.extremity of the yscrew conveyor 154. The lower end portion of theconveyor drive shaft- 162 is journaledwithin suitable bearings 164secured to the shaft126-and itsflower extremity has a bevel gear 166xedtheretox which:v meshes with a cooperating hevel gear l168 fixedA` tothe rear extremity of the screw conveyor. l

Again, itv willbeunderstood that by selectively operating the motorA 156the screw conveyorp154 may be selectively' rotated in either direction.This conveyor is adapted to receive the leading transverse member 5t) ofeachV successive hamper and, through its own rotation, to move thesamefinto` the discharging chamber in conjunction with its. movement. out ofthe ring chamber as av result-ofsacharged hamper being introduced intothe forward endf'rofthechamber.. Itwill be noted that the positionofthesupporting rollers of'each hamper is such thatthe-trailing. end. ofthe same will leave the tracks within thehousing before the trailingtransverse member 50 reaches a position. sufficient to engage the screwconveyor 154. Consequently, as the trailing, rollers. leave the tracks,the trailing end of the hamper will swing downwardly with the connectionofthe leading transverse member with the conveyor acting as a pivot. Inthis manner, the fired contents of each hamper are dumped-into afunnel-shaped bin 170 suitably mounted below the discharging'chamber atits forward end and leading to. the-v receiving land cooling chamber 32.

rA rotary valve assembly, generally indicated at 172, is disposed. belowthe pin 170 so as to control the entrance of the heated4 charcoal. intothe receiving and cooling chamber'v 32. As best. shown in Figure 4, theassembly 172 comprises a substantially cylindrical housing 174 having.anupper opening 176 communicating with the lower endof the bin. 170 anda lower discharge opening`A 178i communicating with the chamber 32.Journaled withinithe housingis a rotatable member 180 including av pairof spaced radial walls interconnectedby a peripheral wall `so asf todeiine a wedge-shaped pocket 182. The member180 is rotated by anysuitable means, such as a motor 184 connected with the shaft thereof, asby abelt 186'andpulleys 188 and 190. l

TheI member. 180 is preferably rotated continuously so that. it.will.make av complete revolution each time au hamper` is. dumped. It will benoted that the construction of the rotary member 180 is such that whenVthe pocket182; is in. communicationwith the upper housing opening 176,the peripheral wall closes the discharge opening1178 and conversely,when the pocket is in communication with the lower opening, the upperopening is closed. The pocket 182 receives a full load of dumpedmaterialthrough the upper opening and during the rotation of the member180, the load is passed through the` lower openingand into chamber 32when the pocket 182 moves into communication therewith.

Thereceivingand cooling chamber may be of any suitable construction andas schematically illustrated in Figure. l, the floor ofthe chamber isinclined downwardly from the valve assembly 172 so that successive loadsfrom thelatter will move downwardly by gravity. The lower end ofthelchamberis provided withl suitablefmeans (not shown) for permitting thecooled charcoal to beremoved `therefrom .withoutsubstantial introductionof air. For example, a valveV assembly similar to the assembly 172 maybe -utilizedfor this purpose. Where gravity feed is impractical, a` dragchain may be provided inthe chamber 32for..rnovingsuccessive loads fromthe valve assembly 1.72 tothe discharge endV of the chamber 32.

Theretort ofthe present invention is adapted to be continuouslyoperated. andtheY time interval in which successive charged. hampers areintroduced intov the retort variesin accordance with the capacitydesired. It will rear end of the firing compartment.

be understood that the empty hampers are first loaded with suitablecharges of material, such as wood or the like, which are to be made intocharcoal. Durin'gthe loading of the hampers 14, the dollies 16 areutilized to handle the same outside the retort so that they may i bereadily introduced therein through the entrance chamber 12. A freshlycharged hamper 14 is moved into the entrance chamber 12 on a supportingdolly 16 by opening doors 22 and moving the dolly inwardly on tracks 38until the leading end engages partition 66. During this movement, thehamper-engaging member 60 is pivoted out of the way and spring urgedback into anoperative position capable of engaging the trailingtransverse member t) of the hamper. Doors 22 ,are immediately closedafter the entrance of the hamper. Eefore actuation of the ram unit 56,the door 2.4 must be opened and, hence, motor 74 is actuated for thispurpose. lt will be noted that the manner in which the hampers are movedthrough the housing 98 is by interengagement with each other and, hencethe movement of a newly charged hamper into the lforward end of thechamber will also result in the movement of a hamper containingcarbonized and precooled charges out of the Consequently, the closuremember 118 of the discharging compartment must be moved from itsnormally closed intermediate position into a position in which theopening 12) is aligned with the rear end of the tiring chamber.Consequently, the motor 140 of the means 30 is simultaneously actuatedwith the motor 74 so that both the forward and rearward ends of thetiring compartment are open.

After door 24 is opened, the hydraulic ram unit 56 is actuated so as tomove the plunger 58 thereof and,`

hence, the member 6@ into engagement with the hamper. This movement ofthe fluid-operated ram urLt 56 moves the newly charged hamper 14 intothe firing compartment and the hamper containing a carbonized andprecooled charge out of the rear end thereof. It will be noted that theleading rollers 54 of the hamper in the entrance chamber are positionedwith respect to the leading end of the hamper so that they will enterthe adjacent ends of the tracks 100 before the center of gravity of thehamper moves beyond the leading edge of the dolly 16. That is, theweight of the hamper 14 is supported by the dollies until the leadingrollers 54 engage within the tracks. Further movement of thefluid-operated ram unit 56 will also engage the trailing rollers 5dwithin the ends of the tracks 100. In this regard, it will be noted thatthe position of the trailing rollers with respect to the trailing end ofthe hamper is such that they will enter the ends of the tracks beforethe trailing end of the hamper leaves the leading end of the dolly. Thatis, the dolly serves to support the trailing end of the hamper until thetrailing rollers 54 enter the tracks 11MB.

At the same time that the ram unit 56 is actuated to move the newlycharged hamper 14 into the tiring chamber, the motor 156 controlling thescrew conveyor 154 is also actuated so that when the leading rollers 54leave the ends of the tracks i! the leading transverse member 50 willfall on the conveyor 154 and be moved rearwardly by the rotationthereof. In this regard, it will be noted that the leading transversemember 50 is disposed ahead of the leading rollers 54 thus enabling thesame to move into an overlying position while the hamper is supported ina horizontal position by the engagement of the lrollers within thetrack. Conversely, the trailing rollers are disposed ahead of thetrailing transverse member so that they will leave the ends of thetracks before the trailing transverse member will have moved into anoverlying position with respect to the screw conveyor 154. In thismanner, as was briey noted above, the trailing end of the hamper isallowed to swing downwardly, with the engagement of the leading trans- 8verse member 50 with the screw conveyor acting as a pivot', and dump thecontents into the bin 170. It will be understood that the leadingtransverse member 50 may be formed with suitable central U-shapedportions (not shown) or the like which would center the hamper thereonand effectively prevent lateral tilting thereof.

When the newly charged hamper has been moved completely into the tiringchamber, that is, at the end of vthe ram unit stroke, a suitable means,such as a switch or the like (not shown), is engaged which serves toVreverse the operation of the ram unit and, hence, retract the same andat the same time reverse the operation of the motor 74 so as to effectclosure of the door 24.

Simultaneous with this movement, the hamper in the discharge chambermoving on the screw conveyorv 154 engages a suitable means, such as aswitch or the like (not shown), when it reaches an inner limitingposition on the screw conveyor. This switch serves to shut off the motor156 or at least reverse its operation and also to actuate vthe motor 140so as to pivot the shaft 126 in a counterclockwise direction as viewedin Fig. S. The initial portion of the movement of the shaft 126 willeffect the closure of the` rear end of the firing compartment by the lclosure member 118 and upon further movement thereof the opening 120registers with the opening 122 to permitrthe hamper to be dischargedtherethrough. When `the shaft has been rotated into its limitingposition, as shown in dotted lines in Figure 5, another switch or thelike, is actuated which de-energizes the motor and again energizes themotor 156 in reverse direction so as to operate the screw conveyor 154and, hence, move the hamper out through the opening 122. At the end ofthis movement another switch is actuated to move the shaft and closuremember to its normally closed position intermediate its limitingpositions.

From the `above it can be seen that for each newly charged hamper which4is moved into the forward end of the firing chamber, there is a hampercontaining carbonized and precooled material leaving the rear end ofAthe chamber. In this manner, the charges are moved substantiallycontinuously through the charging chamber and are handled at each endthereof by means which can be made to operate fully automatic by the useof a suitable electrical circuit or the like, as is well known in theart. As was briey noted above, the operation and position of the burnersin relation to the flow of air suicient to 'support combustion is suchthat the hampers disposed in the forward portion of the tiring chamberare preheated so that the sap and other moisture, in the case of wood,will be driven otf before the charges are moved into a position directlyabove the burners where the heat is most intense. The construction ofthe housing within the walls of the ring chamber is such as to mostefficiently transfer the heat of the burners to the charges of thehampers. The walls of the chambers are highly insulated and a goodcirculation around the entire housing 98 is obtained. The walls of thehousing are preferably good heat conductors, but are also imperforate sothat the pressure within the housing will be maintained v somewhathigher than in the lower portion of the charnber where the ow ofcombustion air occurs. With this arrangement a very rapid heat transferis obtained and the gases discharging through the stack 10S do not carryotf a substantial amount of heat which would be addi- ,Y tionally usefulin carbonizing the charges.

The arrangement also makes possible the recovery of combustible gasesdriven olf from the charges during the carbonization thereof. As wasnoted above, the carbonizing of the charges occurs when the same aremoved through the area of the housing disposed directly above theburners. Since the pressure within the housing is greater than thepressure existing in the lower portion of the chamber, the combustibleproducts of distillation in the form of gases or the like may simply bedirected to the burners through suitable conduits connected between theburners and the interior of the housing. f course, with this arrangementa substantial saving in the amount of fuel utilized to heat the chargesand carbonize the same is effected. After the hampers move past the areawithin the chamber directly above the burners, the temperature isreduced somewhat and the carbonized material is allowed to cool whilewithin the tiring chamber. This precooling of the carbonized chargesbefore discharge from the tiring chamber is significant in that the gasmedium contained within the housing 98 is substantially free from oxygenand, hence, combustion of the carbonized material is precluded. When thehampers reach the rearward end of the tiring chamber the'temperatureofthe charges therein has been substantially reduced. However, if placedin contact with the atmosphere, combustion would result due to itstemperature and the oxygen in the air. The discharge chamber 28 ismaintained closed during most of the operation of the retort and whenthe rear end of the firing chamber is open and communicates therewith,it will be understood that, due to the heat in the tiring chamber, itspressure will be above that within the discharge chamber. Consequently,any ow of gaseous medium between the chambers when they are incommunication will be from the firing chamber into the dischargechamber. In this manner, during the normal operation of the retort thedischarge chamber is also filled with a gaseous medium which is at mostvery low in oxygen content, if not entirely free thereof. At any rate,with the -rear end of the firing chamber in communication with thedischarge chamber the tendency is for the gaseous medium in the formerto flow into the latter. Thus, as the hamper moves out of the ringchamber and into the discharge charnber substantially no oxygen willcome in contact therewith. As was stated above, the action of the rotaryvalve assembly 172 is such as to prohibit free communication between thedischarge chamber and the receiving and cooling chamber. Consequently,the carbonized material is cooled to a temperature below whichcombustion would be caused in the atmosphere, while at all timespreventing contact of any gas which would contain suicient oxygen tosupport combustion. This arrangement insures that a high-grade charcoalwill be produced.

It thus will be seen that the objects of this invention have been fullyand efectively accomplished. It will be realized, however, that theforegoing specic embodiment has been shown and described only for thepurpose of illustrating the principles of this invention and is subjectto extensive change without departure from such principles. Therefore,this invention includes all modifications encompassed within the spiritand scope of the following claims.

I claim:

1. In a charcoal retort, the combination comprising: means dening adischarge chamber for the retort including an arcuate wall having a rstopening therein for receiving successive hampers containing firedcharges of material to be made into charcoal and a second opening fordischarging empty hampers from the chamber; an arcuate closure plate forselectively closing said openings; an upstanding member pivotallymounted about the axis of said arcuate wall and closure plate, meansconnecting said closure plate for pivotal movement with said member; andmeans carried by said member for pivotal movement therewith between arst position in alignment with said rst opening and a second position inalignment with said second opening for handling successive hamperswithin said chamber, said last-mentioned means being operable in saidrst position to engage successive hampers entering said first openingand dump the contents thereof and operable in said second position todischarge successive empty hampers through said second opening.

2. 'Ihe combination as dened in claim 1 wherein said last-mentioned meancomprises a screw conveyor.

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1. IN A CHARCOAL RETORT, THE COMBINATION COMPRISING: MEANS DEFINING ADISCHARGE CHAMBER FOR THE RETORT INCLUDING AN ARCUATE WALL HAVING AFIRST OPENING THEREIN FOR RECEIVING SUCCESSIVE HAMPERS CONTAINING FIREDCHARGES OF MATERIAL TO BE MADE INTO CHARCOAL AND A SECOND OPENING FORDISCHARGING EMPTY HAMPERS FROM THE CHAMBER, AN ARCUATE CLOSURE PLATE FORSELECTIVELY CLOSING SAID OPENINGS, AN UPSTANDING MEMBER PIVOTALLYMOUNTED ABOUT THE AXIS OF SAID ARCUATE WALL AND CLOSURE PLATE, MEANSCONNECTING SAID CLOSURE PLATE FOR PIVOTAL MOVEMENT WITH SAID MEMBER, ANDMEANS CARRIED BY SAID MEMBER FOR PIVOTAL MOVEMENT THEREWITH BETWEEN AFIRST POSITION IN ALIGNMENT WITH SAID FIRST OPENING AND A SECONDPOSITION IN ALIGNMENT WITH SAID SECOND OPENING FOR HANDLING SUCCESSIVEHAMPERS WITHIN SAID CHAMBER, SAID LAST-MENTIONED MEANS BEING OPERABLE INSAID FIRST POSITION TO ENGAGE SUCCESSIVE HAMPERS ENTERING SAID FIRSTOPENING AND DUMP THE CONTENTS THEREOF AND OPERABLE IN SAID SECONDPOSITION TO DISCHARGE SUCCESSIVE EMPTY HAMPERS THROUGH SAID SECONDOPENING.